I have a parallelogram with top side thats says 8x-15
Bottom Side 4x+21
This is how I did it but its wrong
8x-15=4x+21
12x+36=360
12x=324
x27
2007-02-22 12:16:03 · 8 answers · asked by Torrent4223 1 in Science & Mathematics ➔ Mathematics
Dude upstairs beat me to it. I'll assume you recognize your oversight, and not that you don't understand the algebra.
Just use this gimmick: any time a term moves rom one side of the equal sign to the other, the sign of that term changes (in this case, moving the 4x from the right to the left makes it -4x).
And I concur: wassup with the 360? The only thing 360 about a parallelogram is the sum of its angles.
2007-02-22 12:19:18 · answer #1 · answered by Anonymous · 1⤊ 0⤋
8x-15=4x+21 taking 4x to LHS makes it -4x and taking -15 to the RHS makes it +15
4x=36
x=9
2007-02-22 12:22:01 · answer #2 · answered by naughty boy 2 · 0⤊ 0⤋
you added 4x instead of sutracting 4x, and i don't even know where the 360 came from
8x-15=4x+21
subtract 4x for both sides
4x -15 = 21
add 15
4x = 36
divide 4
x= 9
2007-02-22 12:20:30 · answer #3 · answered by 7 · 0⤊ 0⤋
8x-15=4x+21
-4x +15
4x=36
x=9
you needed to minus 4 not add it
2007-02-22 13:46:30 · answer #4 · answered by Cait 1 · 0⤊ 0⤋
Subtr 4x, not add
4x - 15 = 21
4x = 36
x = 9
2007-02-22 12:19:17 · answer #5 · answered by richardwptljc 6 · 0⤊ 0⤋
8x-15=4x+21
(8x-4x)=(21+15)
4x=36
x=9
2007-02-22 12:20:36 · answer #6 · answered by eleshiak 2 · 0⤊ 0⤋
those two equations do not equal each other you have to multiply them. try (8x-15)(4x+21) try it hopefully im right good luck!!
2007-02-22 12:21:29 · answer #7 · answered by ~~ny giants fan~~ 2 · 0⤊ 0⤋
you both added 4x when you were supposed to subtract 4x
and and added a zero to 36 somehow
2007-02-22 12:21:31 · answer #8 · answered by jayphelps321 2 · 0⤊ 0⤋